Configuring Trash in HDFS

Apache Hadoop Provides a trash feature. Trash feature is very helpful for Hadoop Administrators in case of accidental deletion of files and directories. If trash is enabled and a file or directory is deleted, the file is moved to the .Trash directory in the user’s home directory instead of being deleted. Deleted files are initially moved to the Current sub-directory of the .Trash directory, and their original path is preserved. Files in .Trash are permanently removed after a user-configurable time interval and the Administrator can easily restore it to its original location within a time interval.

Files are moved to a user’s trash directory, which is a sub-directory of their home directory named “.Trash”. Files are initially moved to a Current sub-directory of the trash directory. Within that sub-directory their original path is preserved.

Next, follow the below steps to check the trash configuration working by creating a new directory and deleting it.

hadoop fs -mkdir /acadgild_india

hadoop fs -ls /

You can now see that our directory has been created.

hadoop fs -rm -r /acadgild_india

Here, you can see that acadgild_india directory has not been deleted permanently, it is moved to trash only.

Now, where to find it?

Move to .Trash directory inside /user/Hadoop

cd hadoop fs -ls /user/hadoop/.Trash

Next, Move to Current directory-

hadoop fs -ls /user/hadoop/.Trash/Current

Here, you can see acadgild_india directory which we have deleted earlier. Still we have 30 minutes to restore it because we have set a 30-minute time interval for trash updation.

Command to move file from trash folder to Hadoop home:

hadoop dfs -mv /user/hadoop/.Trash/Current/acadgild_india/

Next, Run hadoop fs -ls / to see restored file:

hadoop fs -ls /

Trash has been configured now and working properly.

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